Carbonized polymer-based electronic devices have gained increasing popularity for a wide variety of uses including use as electrodes, electrochemical sensors, and conductive contacts. This may be due in part to such devices exhibiting favorable properties such as bio-compatibility, high electrochemical performance, chemical inertness, mechanical robustness, and a large effective surface area of contact.
Carbonization is a process of converting at least a portion of a material into carbon or a carbon-containing residue via pyrolysis. A typical pyrolysis process involves using a furnace at high temperature in an inert environment. The high temperatures involved place restrictions on materials and processes that could be used for fabrication. Since an entire article is placed within the furnace, it is extremely difficult or impossible to selectively carbonize any particular portion of the article. Many devices, however, benefit from selective carbonization, such as the selective formation of filaments, conductive traces, or sensing regions within an un-carbonized and relatively inert material layer.
One method of selective carbonization utilizes photolithography techniques. While enabling selective carbonization via masking or patterning, such photolithography techniques typically require a clean-room environment, which can significantly add to the cost and complexity of such processes.
Laser pyrolysis has emerged as a technique of selective carbonization that does not require a clean-room environment. Generally, an article to be selectively carbonized is placed into a sealed container with a laser system. The laser system selectively operates a laser to form carbonized pathways along a surface of the article. In existing systems, the interior of the container is maintained as an inert environment in order to reduce a risk of burning material of the article. After the carbonization process is complete, hazardous byproducts from the carbonization process are vented from the container, and the article is retrieved. The need for a sealed container and inert environment as well as the need to vent the container prior to retrieving the carbonized article significantly increases the time, expense, and complexity to manufacturing articles via such processes.
Based on the foregoing, a selective laser carbonization process that reduces the risk of burning would be beneficial. A process that reduces manufacturing time, expense, or complexity would also be beneficial.